1. Field of the Invention
The present invention relates in general to underwater location and communication technology, and more particularly to, a multi-function scuba diver communication device for use by dive partners and dive masters for locating divers, for communicating with divers within dive groups with check diver and alert signals, and for automatically alarming when divers become separated by more than a selectable safety distance.
2. Relevant Background
While underwater, it is very important for divers to keep track of each other. One of the most important rules for scuba divers is to, xe2x80x9calways know where your dive buddy isxe2x80x9d. Because of all the equipment, i.e. mask, snorkel, BCD and tank, scuba divers wear, it is very difficult for them to keep their dive buddy in sight. Scuba diving is an exciting, yet dangerous, sport. Divers can find themselves in several life threatening situations. They can encounter predators or get tangled up in seaweed, wrecks, or amongst their own equipment. It is not uncommon for divers to run out of air or get caught in an undertow. All of these situations can be deadly without the assistance of their dive buddies. Since divers cannot speak to each other underwater, it is often difficult or impossible for a diver to attract the attention of another diver.
Communicating between divers, such as between divers and a dive master or between dive partners, is a serious problem that has not been adequately addressed by current diving devices. Communications are made more difficult by the nature of the environment itself in that most forms of communication depend upon the transmission of light or electromagnetic energy through the surrounding water. Light and electromagnetic energy, however, do not propagate well or consistently through water. Light and electromagnetic energy are rapidly attenuated in water even in optimum conditions, usually within a few feet or even inches, and light is additionally blocked by dissolved or particulate matter in the water. Water varies significantly from location to location and even based on dive depths. Water typically does not provide a uniform acoustic transmission medium as the speed of sound propagation and other signal transmission characteristics vary with water temperature, salinity, and depth (or pressure) each of which may vary with dive location. The inhomogeneous nature of sound propagation in water thereby causes time varying variations in the transmission time between a transmitting unit and a receiving unit, even within a single layer. Therefore, the transmission time between a transmitting unit and a receiving unit vary with the location of a dive (i.e., based on the water chemical makeup) and sometimes even with a planned depth for a dive. These complex variances for the behavior of signals make communication difficult as communication techniques may be effective under certain conditions but prove very ineffective under differing dive and water conditions.
Hence, there remains a need for communication devices, systems, and methods that make it easier for divers to keep track of their fellow divers and to attract their attention when needed during a dive. Such devices, systems, and methods preferably would be adapted for use in varying dive locations and under different water conditions and would be readily adapted for use with multiple divers and dive groups of varying skills and experience.
The present invention addresses the need for underwater communications between dive partners and also between a dive master and divers in dive groups by providing a diver communication device worn or held by divers or attached to a diver buoyancy control device (BCD). The diver communication device includes transmitters, receivers, displays, controls, and data processors and software that enable it to provide a unique combination of communication and diver location functions not available in prior diving equipment. For example, the diver communication device allows two dive partners each using the device to set a dive separation or safety distance between the divers that is monitored by the device on an ongoing basis during the dive and when exceeded, the devices transmit alert signals and an audible, vibratory, and visible signal is provided to both diver communication devices. A tracking device with a display (such as a red, yellow, and green bar graph or light system or directional arrows) is included in each device to enable divers to determine the direction of each other. Diver communications are provided by the inclusion of a xe2x80x9ccheck diverxe2x80x9d function in which a signal can be sent by one diver to one or more divers in their group (i.e., operating on the same frequency or frequencies and using a single diver separation distance) and again an audible, vibratory, and visible display is provided to communicate the receipt of a check diver signal to the other diver or divers. Further, the diver communication device includes a manual xe2x80x9cpanicxe2x80x9d function that allows a diver to manually transmit a panic or emergency signal to a dive partner(s) and/or dive master (e.g., a dive leader).
Because the experience and skill of divers varies and because dive conditions vary, the diver communication device is preferably adapted to allow the safety distance or separation range to be set for each set of dive partners and/or for each dive group (2 or more divers operating with a single safety range and communicating on one or more communication frequencies or settings assigned to that group of diver communication devices). For example, a safety distance may be set at 5 feet for unskilled divers or for dangerous conditions while a fifty-foot, hundred-foot, two hundred-foot, and often higher safety range may be set for skilled divers or relatively safe diving conditions. In one embodiment, each diver communication device is configured to support a plurality of safety ranges (such as 6 to 8 ranges (e.g., set at 10, 20, 30, 50, 100, 250 and the like) or more ranges to provide a wider range of operation).
In one embodiment, a special form of diver communication device is provided for use by a dive master in communicating not just with one diver or dive group but also with multiple dive groups. Generally, the dive master communication device includes receivers and transmitters that enable it to transmit and receive at one or more frequencies utilized by each dive group (i.e., each diver communication device used by a diver assigned to a dive group). The dive master communication device can be operated to monitor separation of the divers in each of the dive groups from the dive master communication device to determine whether the divers are within a safety distance perimeter (or sphere) relative to the dive master. An alert can be automatically or manually transmitted to and from the dive master when the distance is exceeded. The dive master and divers can further communicate by the use of check diver-manual alert signals as discussed for diver communication devices used by dive partners. Typically, a check diver-manual alert signal would be transmitted by a dive master to all of the divers within a group concurrently (such as on a single frequency or multiple signals at multiple frequencies), and likewise, a check diver-manual alert signal transmitted by a diver within a group using their diver communication device would be received by the dive master communication device and by the divers within that diver""s dive group using their diver communication devices.
More particularly, a communication device is provided for use underwater by a diver for communicating with and tracking the location of one or more other divers. The device includes a transmitter and receiver assembly with signal generators, transmitters, and receivers useful for transmitting location signals to and receiving location signals from another one of the communication devices. Significantly, the location signals are transmitted and received on a frequency or frequencies defined by a communication channel setting for the device which allows other divers using other ones of the devices set at a different communication channel to also be able to communicate without interference. A data processor or processing system and devices (such as a CPU and memory along with useful software and/or firmware) is included to process the received signals to determine a separation distance between the two devices and to compare the separation distance to a safety distance. A display and control assembly is also included with a display for indicating the communication channel and the safety distance presently set for the communication device and for indicating (such as with a light, an acoustic signal, with vibrations, and/or with a text message) that the separation distance has been exceeded.
In one embodiment, the display and control assembly includes an input portion, keys, or buttons that are operable by the operator or diver to set the safety distance and/or the communication channel. According to an important feature of the invention the transmitter and receiver assembly is further adapted for transmitting and receiving communication signals, such as check diver and panic or emergency signals. The frequencies used for these signals are also defined by the communication channel such that other divers not in the dive group of the communication device and the other device do not interfere with these devices"" communications. The data processor processes the incoming communication signals to determine the type of signal and to operate the display and control assembly to indicate the receipt of the signal. In one embodiment, a text message is provided that indicates the type of it message received, such as xe2x80x9cCheck Diverxe2x80x9d or xe2x80x9cEmergency.xe2x80x9d To allow a diver to send these signals manually, the display and control assembly includes transmit panic and check diver buttons or keys which when depressed or selected initiate the generation and transmittal of the corresponding message to other devices operating on the communication channel. The display and control assembly may further include a direction indicator to allow a diver to determine the direction of one or more divers. To this end, the transmitter and receiver assembly preferably includes a homing beacon transmitter and receiver for transmitting and receiving a direction signal typically on a different frequency then used for the location signals and the processor operates to determine a direction of the transmitting device for the received signal and operating the display and control assembly to indicate the direction of the transmitting device (such as with red, yellow, and green lights or other direction indicting displays).
According to principles of the present invention, a distance is discovered between a first device and a second device. The discovered distance is compared to a preset distance condition. An alarm is activated when the distance condition is met by the discovered distance or when activated by a user. According to further principals of the present invention, the distance is discovered by any method. One method for discovering the distance is by generating a signal from the first device to the second device and measuring the amplitude of the signal received by the second device then discovering the distance from the measured amplitude of the signal. A second method for determining the distance is by discovering the location of each device and communicating the location of the first device to the second device where the two locations are compared to realize the difference between the two devices. A third method for determining the distance is by the second device requesting a response from the first device and measuring the time between the request and the receipt of the response. The distance is then discovered from the measured time.